<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    //Symbol 表示独一无二的值 解决命名冲突的问题
    //但值不能参与运算
    //symbol定义的值不能用for in 遍历

    //创建symbol
    let s =Symbol()
    console.log(s,typeof s) //Symbol() "symbol"

    let s2 = Symbol('尚硅谷')
    let s3 = Symbol('尚硅谷')
    console.log(s2 === s3) //false

    let s4 = Symbol.for('尚硅谷')//
    let s5 = Symbol.for('尚硅谷')//

    let result = s +100 //报错
    let result1 = s + '100' //报错

    //js的数据类型
    //undefined string symbol
    //object null number
    //Boolean






</script>
</body>
</html>